This invention relates broadly to the art of heat-actuated power plants, and more specifically to apparatus and a method for generating and utilizing energy from a piston which is moved by expansion and contraction of a motivating medium upon thawing and freezing thereof.
A number of United States patents disclose power plants which operate by the expansion and contraction of materials when they are thawed and frozen. Among these are U.S. Pat. Nos. 2,115,501 to Vernet; 2,215,157 to Platzner; 2,884,866 to Patterson; 3,376,631 to Sherwood et al; 3,404,530 to Churchill et al; 3,611,713 to Janous; 3,696,611 to Noakes et al; 3,823,560 to Hansen; and 4,075,845 to Allen.
A difficulty with most of the devices described in the above-listed patents is that they are often unduly large and are relatively slow in operation. Because of the slowness of operation it is difficult to convert large amounts of heat energy to kinetic energy with most of those devices for driving machinery such as airconditioners, and the like. It is therefore an object of this invention to provide a freeze/thaw engine of relatively small size, and a method of operating the same, which converts sufficient amounts of heat energy into mechanical energy to drive many mechanical devices such as air conditioners, irrigation systems, generators and the like.
Yet another difficulty with many of the devices described in the above mentioned patents is that they depend for efficient operation entirely upon ambient air temperatures, which are not always predictable. That is, the fusion materials used therein are frozen by ambient air temperature. It is, therefore, yet another object of this invention to provide a freeze/thaw engine which does not unduly depend upon, ambient air temperature for proper operation.
There appears to be a need for an engine which can be driven by heat at a relatively low temperature in order that machinery can be driven from such sources as waste heat, solar cells, and the like. That is, there exists heat engines which can be driven by fluids at high temperatures, such as by steam, but there does not appear to be a commercially practical, and dependable, engine which can be driven by heat in the temperature range of from 70.degree. to 120.degree.. It is an object of this invention to provide such a engine and method of driving the engine.
It is a further object of this invention to provide an effective system for utilizing energy from the temperature differential between ambient water and a warm water source.
It is a further object of this invention to provide such a system which can be driven with warm and cold tap water.
There also appears to be a need for a engine which can be efficiently driven both from intermittent, low temperature-type sources, such as waste, heat and solar cells, and from steadier high temperature sources such as combustion devices, and heat pumps and the like. It is an object of this invention to provide such an engine.
It is a further object of this invention to provide an engine and system to perform work which does not require the use of fossil or other combustible fuel, but rather uses instead, less expensive energy such as sunlight, waste heat from other sources, and geothermal energy.